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puzzling observation by stereophile

Footnote 1: One anomaly I found when I unpacked the SabrinaX was that even with the loudspeaker not connected to an amplifier, I could hear a very low-level hum coming from the midrange unit. The level of this hum varied with the position in the room and the orientation of the loudspeaker. The hum frequencies were primarily 180Hz and 300Hz. All I can conjecture is that the iron, steel, or ferrite core of an inductor in the midrange crossover circuit was picking up the hum field from my home's AC wiring. When the speaker is connected to an amplifier, the latter's very low output impedance should damp the hum. This is more a curiosity than a concern.


  • Say what?? That's a ridiculous theory. He knows that our power here in the US is 60Hz.

    The comments section on this is entertaining, as usual.

  • Yeah- bogus unfounded theory for cause.

  • Aliens?

  • Those frequencies might be from lighting. Eather way a big concern as none of those components should be easy to excite.

  • Interesting though that 180 Hz and 300 Hz are both multiples of 60 Hz. Second and fourth order harmonics coming into play somehow?

  • I wonder if there is a Russian embassy nearby?

  • Or Cuban... haha.

  • @kenrhodes said:
    Or Cuban... haha.

    And they told me I'd never find a use for this carbon fiber lined tinfoil hat. HA!

  • Some dirty AC there. JA didn't have his audiophile cables and power conditioner hooked up yet. :o

    ............. could you hum a few bars.
  • I would like to see some type of measurement of that. I would argue in the world of commercial and DIY audio we would have come across such a thing at some point, and solved it. Maybe he has a ceiling fan or something that is screwing with him. I have, for shits and giggles, measured the hum from a transformer in the past but it was also live on one side and loaded down on the other side and it was really not much of a hum and it was right at 60Hz. Visiting the various dams on the Missouri River in SoDak where we generate megawatts of energy there can be an almost tactile 60Hz hum as you stand near the first substations, but again - gobs of electrons flowing there.

    I'm not sold on this not being related to something else in the room, like a fan exciting a resonance on the midrange or something or JA is finally losing his marbles. If it was as simple as stray AC exciting an inductor in a crossover I suspect it would be an extremely commonplace phenomenon, no?

    I have a signature.
  • Did they recently legalize weed in his state? If so, I want to try whatever he's been smoking.

  • edited March 3

    Forgot where he lives. Is it possible he lives on, or near a rooftop, with high powered transmitters ... but wouldn't this result in singing?

  • Sometimes when I have been soldering wires to drivers in final assembly, I can hear a hum from one or more of the drivers, but that's pretty close spacing. Shame on JA for not chasing down the cause. For one thing, this might influence his listening tests or even measurements if not remediated.

    Don, Donno, or "Hey you" all work for me, But never "Mr Johnson"
  • This topic fits right in with Danny Richie's claims that RF can get in your speaker cables and ruin your listening experience. But there's a direct business incentive in Dannie's case. I see he's now selling some braided wire kits to the ignorant with more dollars than sense - complete with Tube Connectors. I'm just glad Amir at Audio Science Review provided a little demonstration of why Dannie's claims are pure hogwash. There was even a nod at a monetary challenge.

  • Is Amir , AJ from Florida?

  • Amir is the guy behind audio science review. And I think he is in Seattle.

  • For this review simply shorting the speaker terminals should have stopped the noises. Could have even tried to ground the negative terminal (check your grounds first!). Both passive ways to address the issue.
    Inductance like this can be easy to come across if you are in commercial buildings or near large transformers, high power lines, and more recently cell phone towers. I have a Samsung A11 cell phone and it interferes with almost all of my audio equipment if its within a 2 foot radius, even passive devices like drivers and headphones.
    Don't get me wrong I'm not saying this is so prevalent we are all dealing with it like some would have you belive. Most of us are not so close to high voltage to get this level of interference and well designed products can filter a lot of EMI out of the signal path.

  • I had tested the variation of a tweeter inductor in different positions near my woofer magnet and woofer inductor with a DATS. In certain positions, I could clearly hear the sweep through the woofer. So, I suppose it is possible.

  • When Rory lived in Lafayette, he at one point was just about a block from the 'transmission station', or whatever it was called. I was down there playing a pair on his HTPC through the Hafler at the time, and the sound was definitely edgy. During listening post power-filter installation, it was notably better.

  • If Tesla was able to 'transmit' electricity wirelessly for hundreds of feet, I can believe that some kind of stray voltage flying around this testers apartment could have caused an audible noise in a speaker driver.
    I've heard boosted CB and HAM radio transmissions through land line phones that were on the hook and not even in operation at the time. Once I heard voices coming from the front office at my other job and went out there to see nobody there. A few seconds later I heard voices again and saw the lights on the phone lighting up on and off. What the heck?
    Boss came into the office a few minutes later (their house was in front of the office in another building) and I mentioned what happened, thats when he told me he was talking to the other side of the world on his HAM rig. The line antenna was right over the office building.
    Electrons are kind of in their own world.

  • edited March 21

    It is said he lit bulbs for two miles at his Colorado Springs lab.

    Tesla, the greatest mind eVeR.

    I like this simple demonstration of transmitting power wirelessly.

    NASA successfully experimented with wireless energy transmission.

    A different take with a commercial option for the wireless transmission of energy.

    Back when when CB was popular, it wasn't to uncommon for a neighbor to complain about hearing voices over their tv or messing up reception. Sitting in the parking lot of a local grocery store, I could key up the cb and it could be heard over the pa in the store. That's why I wondered if he might live near some kind of transmission tower.

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